Skip to end of metadata
Go to start of metadata

http://www.webpagetest.org/result/110314_KT_5AHD/1/pagespeed/ makes these key recommendations:

  1. Leverage browser caching
  2. Parallelize downloads across hostnames
  3. Enable compression
  4. Combine images into CSS sprites
  5. Minify CSS

The first three are server-side changes, the latter-two can be done by Web Services.
See Webserver config change requests.

For the minification and concatenation of CSS and JS we could look at http://code.google.com/p/minify/ as tool to get us started.

Google's online Page Speed tool gives these results

Page Speed results April 1 2011

Icon

High priority. These suggestions represent the largest potential performance wins for the least development effort. You should address this item first:

  • Leverage browser caching

Medium priority. These suggestions may represent smaller wins or much more work to implement. You should address these items next:

  • Combine images into CSS sprites,
  • Optimize images

Low priority. These suggestions represent the smallest wins. You should only be concerned with these items after you've handled the higher-priority ones:

  • Inline Small JavaScript,
  • Defer parsing of JavaScript,
  • Minify CSS,
  • Minify HTML,
  • Minify JavaScript,
  • Specify a Vary: Accept-Encoding header

Additionally there are other standard practices we should be following:

  1. load JavaScript at the bottom of the page rather than the top
  2. optimize images
  3. Late loading of resources where not immediately necessary (images/HTML that are off-screen or accessible via JS, images/JS/HTML loaded later in the document where not immediately needed) - for example, work from China page loading time can be seen here - click on Agent Location.
  4. Reduce the number of requests where possible (CSS sprites, concatenate CSS and JS)

Other notes

Phil also suggest creating a JSP that works out what Javascript/CSS to include from the various ones specified for a page. This would reduce the number of requests massively. Many of the resources are specified as a page property, and we already know what the template would use.

Liam has also pointed out images may not be correctly compressed and looking at http://www.webpagetest.org/result/101101_A72Y/1/performance_optimization/#compress_images it indicates a saving of 309.8 KB.

We have not yet looked at optimising our HTTPS serving. There is a resource here http://blog.httpwatch.com/2009/01/15/https-performance-tuning/ which appears useful.

Resources

  • No labels